The invention relates to virus infections, and more particularly relates to treatment of human papillomavirus (“HPV”) in living subjects. In its most immediate sense, the invention relates to treatment of type 11 human papillomavirus using certain ribonucleases (RNases), namely ranpirnase (known also by its registered trademark ONCONASE) and the '805 variant of ranpirnase described below.
Ranpirnase is an RNase. It is disclosed and claimed in U.S. Pat. No. 5,559,212. It has been tested and found to be cytotoxic to cancer cells because of its enzymatic activity against RNA. The second embodiment disclosed and claimed in U.S. Pat. No. 5,728,805 (hereinafter, the “'805 variant”) is also an RNase, and has likewise been found to be cytotoxic to certain cancer cells. The '805 variant is a close variant of ranpirnase; its amino acid sequence is identical to that of ranpirnase except that it has valine instead of isoleucine at position 11, asparagine instead of aspartic acid at position 20, and arginine instead of serine at position 103. (In the drawings, the '805 variant is referred to as “Val11, Asn20, Arg103—Ranpirnase”.)
Presently, there is no satisfactory treatment for HPV infections. While vaccines (e.g. those available under the GARDASIL and CERVARIX trademarks) can prevent infection with HPV, for patients who are infected with HPV existing treatments (cellular immune inducers and anti-mitotic agents) are ineffective. This is of concern because HPV infections can develop into cervical cancer.
Ranpirnase and the referenced '805 variant have been discovered to be surprisingly active against certain HPV infections. Ranpirnase is known to be non-toxic and well-tolerated in humans, and the other RNase is believed to share these qualities. In accordance with the invention, HPV infections, and particularly type 11 HPV infections, are treated using these RNases by administering them in therapeutically effective amounts.